NEEMA Funded Projects by Topic Area - Viral Hepatitis
NEEMA 2.0 (2019-2024)
Only a fraction of hepatitis A, acute hepatitis B, and acute hepatitis C cases are reported through the National Notifiable Disease Surveillance System to CDC. There are several barriers to ascertaining and reporting acute infections, including the fact that many people with viral hepatitis infections may not develop symptoms, may not seek care if they become symptomatic, or may not be reported to public health authorities if they do receive medical care. Currently, CDC estimates the incidence of viral hepatitis A, B, and C infections using three probabilistic multiplier models. This project will update and improve the methodology used to estimate the incidence of acute viral hepatitis cases in a number of ways. First, it will upgrade the structural model to a hierarchical framework and include covariates that can predict variation in each of the three adjustment factors (capturing probabilities of symptoms, care-seeking, and capture in the surveillance system). Second, it will incorporate time series and stratum-specific estimates of underlying incidence and corresponding case notification data. Finally, it will focus on joint modeling of hepatitis A, B, and C incidence, ascertainment and reporting, with synthesis of available evidence relevant to each and accounting for shared processes.
Widespread hepatitis A virus (HAV) outbreaks are ongoing in 30 states due to person to person transmission, resulting in over 27,000 reported cases, and 275 deaths. Key risk groups for these outbreaks are drug using populations, homeless individuals, and men who have sex with men (MSM). Local health departments urgently require information on target vaccination levels to prevent outbreaks and achieve herd immunity. Previous studies estimating target vaccine coverage required for preventing HAV outbreaks have been limited to endemic transmission and universal vaccination as opposed to specific at-risk populations. This work will combine the state-level and national data on HAV outbreaks with dynamic modeling to understand herd immunity thresholds among, and transmission patterns between, the following at-risk groups: homeless populations, drug user populations, and MSM. Developing a tool for counties to estimate required vaccination numbers and associated vaccination budget is also planned.
The most recent CDC hepatitis B screening guidelines were published in 2008. Since then, three additional risk groups (persons co-infected with hepatitis C, persons with current or history of sexually transmitted infections, persons with current or history of incarceration) and testing strategies (HBsAg only; anti-HBc followed by HBsAg if anti-HBc-positive; HBsAg and anti-HBs; or HBsAg, anti-HBs, and anti-HBc) have emerged. Cost-effectiveness analysis for hepatitis B screening strategies in at-risk populations will inform the next iteration of CDC testing guidelines. This project will estimate the cost-effectiveness of hepatitis B screening in persons with a history of or current STDs, a history of or current incarceration, or co-infection with hepatitis C, and will examine the cost-effectiveness of universal screening for persons born before 1991 (time when universal hepatitis B vaccination recommendation was implemented). For each group, it will assess the cost-effectiveness of different testing algorithms based on various combinations of the 3 HBV seromarkers (HBsAg, anti-HBs, and anti-HBc).
There is now clear evidence that one-time routine HCV testing for adults in the US is cost-effective, and various guidance bodies are considering expanding guidance for routine HCV testing to include all adults. Expanded guidance for routine HCV testing includes ongoing, periodic testing for patients at high-risk, such as PWID, but there is no evidence to inform the optimal testing interval among high-risk persons, nor the cost or cost-effectiveness of intensive and frequent screening. This project will use previously developed agent-based network model of HCV transmission across injection-drug-using networks to: identify the minimum HCV testing frequency needed to achieve HCV elimination among PWID, to estimate the cost of such screening and treatment, and to measure the cost-effectiveness of various screening frequencies
As an increasing number of states are beginning to tackle state-wide hepatitis C elimination plans, the success of these initiatives is likely to depend on effectively addressing the high prevalence of HCV infection and its risk factors in correctional populations including jails and prisons. Previous studies focused on evaluating a range of strategies for HCV testing and treatment in prisons and found that such strategies could provide high value for funds needed. Jails differ from prisons in several ways that present logistical and cost challenges for scaling up HCV testing and treatment. Jail sentence durations are typically short, meaning that most people who initiate HCV treatment in a jail will need to be linked to a treatment provider in the community upon release. Jails typically do not have available resources to support large-scale HCV treatment, nor adequate infrastructure for tracking patients and linking them to community care. This project will focus on optimizing HCV testing and treatment strategies in jails and, thus, explore the clinical and public health benefits of different strategies, identify screening and treatment implementation models that provide good value for the resources invested in scale-up, and estimate budgetary impact from the jail perspective.
In the United States, injection is an increasingly common and high-risk route of administration for prescription and illicit opioids as well as other drugs such as methamphetamine. Unsafe injection drug use (IDU) behaviors increase risk for bloodborne infectious diseases such as hepatitis C virus and HIV, making these infectious diseases secondary but deleterious consequences of the opioid crisis for persons who inject drugs (PWID). Due to the stigmatized and illicit nature of non-medical IDU, population-level prevalence is difficult to measure using survey methods typically used to monitor health-related behaviors. Estimation of national IDU prevalence is critical for informing infectious disease prevention efforts among PWID. The current national PWID population size estimate is based on household survey data from 2011 and does not reflect the current opioid and methamphetamine injection. This project will update the PWID prevalence estimates nationally and for specific subpopulations of interest.
PWID are at high risk for multiple blood-borne and sexually transmitted infections including HCV and HIV. National and state-level planning on syringe services programs (SSPs) and medication-assisted treatment (MAT) rely on accurate estimation of PWID population numbers and understanding of how these interventions impact HCV and HIV transmission among PWID. The particular structure of injection networks and sexual networks among PWID leads to heterogeneous risks of infection transmission and acquisition across the PWID population. In addition to syringe services and treatment for underlying opioid use disorder that leads to injection risks, many other preventive modalities are available for both HCV and HIV, including biomedical interventions (e.g. HIV pre-exposure prophylaxis, HIV treatment, HCV treatment); and behavioral interventions (e.g. promoting safer injection practices, condom use.) Different interventions can interact with each other and generate synergistic (or antagonistic) effects on the control of HCV and HIV transmission. What determines the optimal intervention package is unknown. This project will extend the existing agent-based network model of HCV transmission among PWID to: (1) determine the levels of SSP coverage needed to reduce new HIV and HCV infections among PWID by 25%, 50% and 90%, (2) compare the population health and economic impacts of different levels of program coverage for opioid use disorder, (3) identify intervention combinations across the array of different prevention modalities that may produce substantial reductions in HCV and HIV burden among PWID, and (4) compare the cost-effectiveness of different intervention packages.